A reader asked over at the report of Microsoft's Quarterly Report what number of phones worldwide use the various mobile operating systems. Well as fate may have it, the answer fell in out laps this morning.

Electronista.com is reporting on an AdMob March 2009 report that shows how each OS stacks up worldwide and in the United States.

According to the report, in the U.S. Apple has approximately 50 percent of traffic where RIM gets 22 percent. Windows Mobile has 11 percent in its home arena, and both Android and Palm lay claim to 6 percent. Hiptop represents 4 percent while Symbian earns just a single percentage point. Worldwide, Apple drops to 38 percent, RIM is at 11 percent, Symbian 37 percent, Palm and Android are at 3 percent, Hiptop at 2 percent and Windows Mobile comes in with 6 percent.

The one caveat on these reports, they are based on AdMob's advertising requests and not necessarily sales figures. AdMob is a mobile advertising marketplace, offering solutions for discovery, branding and monetization on the mobile web. So while this bodes well for Apple in the U.S., the report is based on ad sales as opposed to unit sales.

I am sure that the sales figures will be slightly different.  Microsoft reportedly selling 20 million units worldwide in 2008 and Apple claims 37 million units sold.  The one problem with Apples sales figures is that it combines the iPhone and iTouch; a trend that is becoming more popular with Apple.  I wonder if Microsoft includes PDA's that run Windows Mobile in their stats?